Means for adjusting high-frequency electric discharge devices



Patented Feb. 27, 1951 MEANS FOR ADJUSTING HIGH-FREQUENCY ELECTRIC DISCHARGE DEVICES William Thomas Gibson, London, England, assignor to International Standard Electric Corporation, New York, N.

Delaware Y., a corporation of Application June 19, 1947, Serial No. 755,599 In Great Britain October 16, 1940 `section 1, Public Law 69o, August 8, 1946 Patent expires October 16, 1960 This invention relates to electron discharge devices for operation at high frequencies.

In such devices Vit, is sometimes desirable to provide a metal diaphragm `which can be .adjustably deformed under the control of means external to the evacuated container or envelope of the discharge device, for the purpose of, for ex.- ample, tuning a resonator structure contained within the envelope. Where this adjustment is made by mechanical means the obvious construction involves the use of a number of brazed joints which have to hold a vacuum. This involves a difficult construction and, moreover, failure of a brazed joint will cause complete loss of the tube.

It is an object of the invention to provide ya means for adjustably deforming a diaphragm in an electron discharge 'l device without the employment of brazed joints. The construction is thereby simplied and reduced. 1

According to one aspect of the invention a thin metal diaphragm entirely enclosed within the evacuated container is adapted to be moved through the intermediary of a movable member attached to a flexible metal member, such as a bellows, sealed in a glass portion of the container and constituting part of the wall thereof.

The invention is especially applicable to electron discharge devices incorporating hollow resonators within an evacuated container and according to a further feature of the invention such a resonator is tunable by means of athin metal` diaphragm which is located entirely within the vacuum,the container comprising a glass re-entrant stem portion in the length of which is interposed a corrugated metal bellows and which is closed at its inwardly-projecting end by, for example, a glass press, the diaphragm being movable through the intermediary of a member secured to the movable end of the stem portion.

According to a still further feature of the invention, in an electron discharge device of the electron velocity modulated type, a hollow resonator is constituted by a metal tube in the inside of which is provided a pair of spaced apertured metal discs one of which comprises a thin diaphragm, the tube forming part of the wall of the evacuated container end being sealed at one end to a glass bulb to which is sealed a re-entrant stem in the length of which is interposed a corrugated metal bellows and which is closed at its inwardly-projecting end by, for example, a glass press, means being provided adapted to move the inwardly-projecting end of the stem in a direcmanufacturing difficulties 6 claims. (Cl. 25o- 275) l tion parallel to the axis of the tube and thereby,

through the intermediary of a member connecting the diaphragm and the stem, to deflorm the diaphragm for the purpose of tuning the resonator.

' embodiment of the invention applied to a velli ` locity modulated tube of the Klystron type,

Referring to the drawing, I is an outer copper tube which may, if necessary, be cooled by water or air blast or other means. At each end of this tube the copper is flared out as shown yat 2 and 3, and turned to a knife edge. To this is sealed a glass bulb by means of a Houskeeper seal.

At the cathode end a stem is sealed, in which carries, for example, a flat cathode 4 heated by an indirect heater, and cylinders 5 and 6 connected by wires to the outside, whichV can be used at different potentials to form an electrostatic lens system to project the parallel beam of electrons down the whole length of the tube. A disc carrying a piece of tubing l all made of copper, and a similar one shown at 8, are brazed on the inside of the tube l and together form a hollow resonator. An extension of the tube 8 as shown at 9 constitutes a drift tube in which bunching of electrons occurs, and a similar resonator is built at the other end of this drift tube. As it is necessaryto tune this resonator to the first one, it is necessary to make one part of it deformable. This can be done with diaphragm I0 which carries the tube H. Diaphragm I0 can be made of very thin copper brazed to the inner tube and the outer tube. The loop of copper wire shown at l2 can be used in known manner to secure feedback between the two resonators, known in order as the buncher and catcher, to provoke oscillations. At the catcher end of the tube, a bulb is sealed on at 3 and into this is sealed a stem which has for part of its length a short section of corrugated copper bellows shown at I4 which is sealed directly to the glass at each end at l5. On the other end is then sealed a press 22 which carries a central wire or rod leading to an electrode I3 which can collect the electrons which pass through the tube.

Upon the stem, and electrically connected to the bellows I4, is mounted a collar which carries a ysection of copper tube shown at I6. The projecting end of this copper tubingV carries a The electrode' connection through the stem is extended in a copper rod 20 which is threaded.v Y v During the exhaust of the tube, which can be carried out through a tubu1ation-28,.theftendency of the bellows l5 to open is controlled by wedging the rod 20 into a Xed posiltion-witlirespectto the end of the bulb by any suitable means. After Vthe exhaust ofthe tube is complete, a collari8 is mounted on the outer surface of therbulbpand this carries a metal support I9 upon which a nut 2|, which has been threaded on; the;'i'.oellll;` can" bear. By this means it is possible tofs'crewf `v the nut 2| which withdraws the diaphragm-W` towards it, thus effectively-icarrying out the operation of tuning the resonator. Motionin the reserve direction is automatically carriedout` when the nut isunscrewed by theairpressure tending to4 suck the stein inwards. j f

On the side of the outer' tube' l is mounted a copper tube 24 brazed at 23 to the tube I. VTo this at 2-5Y is sealed' a piece 'ofv glass tubi'ng -251 into whichI is then sealed av central conductor Zi'which ends# in a loop proiecting into the resonator. This` unit' forms a -coaxial conductor throughr whicheathe power' generated in the 'hollowJ reseii'ia-fn tormayberemoved-.J Y i In this construction the brazedf joint 2'3 is the only brazed' joint i-n thedevice whi'chfhastomaintain a vacuum. The mechanism; for moving the have to maintain tlielvacuuni.` i Y v It` is tobeunderstood that the invention is. not limited tothe embodiment. described above del tail nor to the application toV electron velocitymodulated: tubes.l Other applications andi modications coming within'ther scope'k of the'. invention as denedgin the appended claims wills'readily occur to thoseversediin the art.

What is claimed is: Y.

l; An; electron discharge tube of. the velocity modulation type comprising evacuated 'ene yelope: including: arzglass` stern havingV a# flexible corrugated metalbe'llows: interposed'Y in: the length thereof for making vaportionof sard'stenr move able with respecttosaid? envelope; a cavityreso'- nator mounted in said envelope,y tuning means connected to said resonatorandamember se# cured to. said tuning means and 'toi the movable portion of said'vglass stem.,

2. An electron di'schargetub'e of the: velocity diaphragm y Ill'l involves no brazedj'oints which v modulation type comprising an evacuated envelopeiincludingfa reen-trant;glassI stein having a iiexible! corrugated metal bellows: interposed in the length thereof and a glass press closing the inwardly projecting end of said stem, said glass press beingmovabla a cavity resonator mounted in said; en'velopej,A a'thn metal diaphragm forming a wallfor 'said` resonator and means secured to said movable. press and to said diaphragm for permitting tuning. of said resonator.

3;l An'felectron'fdischarge device according to claim 2 wherein a central grid tube is mounted in anapertu e in svaid diaphragmand said means compr'iseisf'aiv 'etaltube, one end attached to said grid tube and the other end mounted upon said *rr'electron discharge device of the velocity modulation type comprising an evacuated envelop'e including a glass bulb and a reentrant glass stem in 4said bulb havingmetal bellows interposed in tlelengtl'rthereofiantl aI glass press closing the inwardlyv pr-iectirigiend of said ster-iry` said glass press being' movable with" 'respect'to saidbulb; a cavity* resonator in said envelope including a metalf'tube forming part 'of saidenvelope,- bei-'ngf'sealed to said glassbulban'dfa pair-ofspaced emertured metal-"discs mounted' transversely in saifd'tube, one'x of said: discsi being flexible, andata member secured:y to saidpressY and tof said flexible disc'- to deform saidjfdl'sc` in 'a direction ,parallel totheaxi's ofsai'd' tube to tune said resonator..-

5. 'An electroni" dische'ngeA device? accordin'gto claim 4 wherein a-z collectingelectrode is mounted upon; said; press;l

6. An electron discharge device of theaelectron velocity modulated type accord-ingetof claim i wherein said resonator; constitutesacatcherv reso-- natona-nct which further comprisesa launcher resonator vincluding an. exteryision.ofV said tube and a. further painotspaeed; andv apertured meta]` discs mounted transversely therein, a wire feedgback loop being4 provided withingsaid; tubebetweensaid catcher resonator andv said;` bunchenresonatori,

WILLIAM-.moms 7 REFERENCES @man The following references are of recom: the 'epf'ths Patent: .Y 

